@max Synchronizing calendars in both directions is a very complex task, and it takes more than just downloading and uploading a single .ics file per calendar. If you have a look at CalDAV and which problems it solves, you will see what the problems are. You will also need a hierarchy: just think about the case that one .ics file contains a certain event, and the other doesn’t. So, does it mean that it has been deleted by the user and should be deleted from the one .ics file, too, or has it just been added and should be added to the other .ics file?
Calendar Colors randomly reset to different colors
I use ICSx5 in combination with DAVx5 to synchronize calendar links from Nextcloud onto my phone. DAVx5 and Nextcloud correctly display the colors of the calendars that I set in my NextCloud settings (blue and yellow respectively).
On initial sync, ICSx5 also gets these same colors, and the color is also correctly shown in my calendar App, Etar.
After a while, though, ICSx5 (and therefore also Etar) suddenly switches the color to dark green and violet for the two calendars. Setting the color back manually to the color from NextCloud or even a different color doesn’t matter, after around half a day it always goes back to dark green and violet for the two calendars.
One of the two calendars in question is public, so I can share the link (https://calendar.google.com/calendar/ical/2904.cc_lq509kkank97fftfkjm3gmbq70%40group.calendar.google.com/public/basic.ics). The other calendar is private, so I will not share it here.
Device Info: Huawei Honor 9
App Info: ICSx5 1.8.9, DAVx5 3.3.1
Both DAVx5 an ICSx5 are whitelisted in the battery settings to be able to run in the background.
Are there any other apps which could set the calendar color? I doubt it comes from DAVx5 or ICSx5…
The only other Calendar-related app on my device are the built-in Huawei Calendar (that I don’t use), which I can neither uninstall nor disable. It seems that when I open the settings in that app, it did change the colors.
I’ll investigate this, and see if I can keep it from doing that.
I found an article describing the phenomenon, and it seems to be a known issue with workaround: https://www.solvemix.com/index.php/en/year-2019/huawei-p20-pro-calendar-colors-change-regularly-solution.html
I’ll try the solution from there, which is to remove the Calendar permission from the Huawei Calendar app.